[moderation] [fs?] KCSAN: data-race in select_collect / step_into

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: d2f51b3516da Merge tag 'rtc-6.7' of git://git.kernel.org/p..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16d6acc0e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=f89e9ee49649fd75
dashboard link: https://syzkaller.appspot.com/bug?extid=638149d92346cbf3013c
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [bra...@kernel.org linux-...@vger.kernel.org linux-...@vger.kernel.org vi...@zeniv.linux.org.uk]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/89fee4978f05/disk-d2f51b35.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/acdc29bb8759/vmlinux-d2f51b35.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6829e88f9c27/bzImage-d2f51b35.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+638149...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in select_collect / step_into

write to 0xffff8881066e9900 of 4 bytes by task 10517 on cpu 0:
d_lru_del fs/dcache.c:437 [inline]
select_collect+0xb3/0x2a0 fs/dcache.c:1565
d_walk+0x291/0x460 fs/dcache.c:1386
shrink_dcache_parent+0x85/0x1a0 fs/dcache.c:1625
vfs_rmdir+0x283/0x2f0 fs/namei.c:4193
do_rmdir+0x194/0x320 fs/namei.c:4248
__do_sys_rmdir fs/namei.c:4267 [inline]
__se_sys_rmdir fs/namei.c:4265 [inline]
__x64_sys_rmdir+0x30/0x40 fs/namei.c:4265
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff8881066e9900 of 4 bytes by task 10516 on cpu 1:
__d_entry_type include/linux/dcache.h:386 [inline]
d_is_symlink include/linux/dcache.h:416 [inline]
step_into+0x12f/0x800 fs/namei.c:1845
open_last_lookups fs/namei.c:3569 [inline]
path_openat+0x10da/0x1d70 fs/namei.c:3776
do_filp_open+0xf6/0x200 fs/namei.c:3809
do_sys_openat2+0xab/0x110 fs/open.c:1440
do_sys_open fs/open.c:1455 [inline]
__do_sys_openat fs/open.c:1471 [inline]
__se_sys_openat fs/open.c:1466 [inline]
__x64_sys_openat+0xf3/0x120 fs/open.c:1466
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x00080000 -> 0x00008000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 10516 Comm: syz-executor.5 Not tainted 6.6.0-syzkaller-14651-gd2f51b3516da #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.